Haec species a congeneris ad Leptoaenam sensu stricto pertinentibus foliis glabris apice obtusis usque rotundatis, involucro ellipsoideo plerumque glabro interdum sparse albido-hirsuto c. 7 mm alto sepalos omnino includente atque staminibus tantum 6 ad 8 distinguitur.
Shrubs to 2 m tall; stems glabrous to sparsely pubescent. Leaves subcoriaceous, elliptic to slightly obovate, 2.4 - 4 X 1.1 - 1.7 cm, glabrous, discolorous when dry, dark olive brown above, lighter olive green below, base cuneate to acute, margins strongly revolute, apex rounded, venation weakly brochidodromous, secondary veins c. 8 per side, midrib flat above, raised below with very sparse scattered trichomes or glabrous; petiole 2 - 3 mm long, 0.6 - 0.8 mm diam., shallowly canaliculate, stipules caducous. Inflorescences axillary in the terminal leaves, 2 - 8 - flowered, axes sparsely to densely puberulous; peduncle 1 - 2 mm long, distinct, involucre ellipsoid to oblong, glabrous, 7 mm tall, 3 mm diam., apical margin with 8 narrowly triangular, subequal teeth 1 mm tall, 1 mm broad at base, glabrous or sometimes sparsely short whitish hirsute; sepals completely included within the involucre, 4 X 4 mm, circular, strongly inrolled, densely whitish hirsute outside, glabrous inside; petals narrowly oblong, 12 X 3 mm, clear yellow with evident venation upon drying, glabrous, exserted 5 - 6 mm beyond involucre; stamens 6 - 8, free to the base, filament 8 - 10.5 mm long, anthers unknown; ovary ellipsoid, 1 mm diam., densely whitish golden hirsutestrigose, the trichomes to 2 mm long, style 11.5 mm long, slender, exserted 4 - 5 mm above involucre, stigma capitate, 1 mm in diam. Fruit unknown.Fig. 7.
Leptolaena masoalensis is known only from the type collection made at Ambato, a hill in the northeastern part of the Masoala Peninsula (Fig. 6) well known for its large population of Nepenthes masoalensis Schmid-Hollinger . At first glance, L. masoalensis may be mistaken for L. delphinensis , with which it shares leaves with an obtuse to rounded apex. However, L. masoalensis can be easily distinguished by its much larger, ellipsoid to oblong involucre 7 mm tall, sepals that are completely included within the involucre at anthesis, and leaves with only 8 secondary veins per side versus (8 -) 11 - 12 in L. delphinensis .
Conservation status.With an area of occupancy <100 km 2, and only a single known population that appears to lie just outside the limit of Masoala National Park, L. masoalensis is assigned a preliminary status of Critically Endangered (CR).
Leptolaena masoalensis is a species of flowering plant in the Sarcolaenaceae family. It is found only in Madagascar. Its natural habitat is subtropical or tropical moist lowland forests. It is threatened by habitat loss.
Leptolaena masoalensis is a species of flowering plant in the Sarcolaenaceae family. It is found only in Madagascar. Its natural habitat is subtropical or tropical moist lowland forests. It is threatened by habitat loss.
